Hydroconversion catalyst preparation methods

ABSTRACT

IN A HYDROCONVERSION PROCESS WHEREIN A HYDROCARBON FEEDSTOCK IS CONTACTED WITH SOLID CATALYST PARTICLES PREPARED BY FORMING A HYDROGEL AND THEN SHAPING THE HYDROGEL INTO A PELLET, AND WHEREIN SAID CONTACTING IS CARRIED OUT AT A TEMPERATURE BETWEEN 400 AND 900*F., AND A HYDROGEN PARTIAL PRESSURE BETWEEN 100 AND 10,000 P.S.I.G., THE IMPROVEMENT WHICH COMPRISES PREPARING SAID CATALYST BY ADDING TO SAID HYDROGEL A CATALYST FINES-WATER MIXTURE CONTAINING AT LEAST 10 WEIGHT PERCENT FREE WATER AND AT LEAST 80 PERCENT TOTAL WATER, BEFORE THE HYDROGEL IS SHAPED INTO A PELLET.

United States Patent HYDROCONVERSION CATALYST-PREPARATIONBarry,S.,Morgan,, Concord, and Joseph Jalfe, Berkeley, Calif.,'assignors' to Chevron Research Company San Francisco, Calif. i NoDrawing. Filed Nov. 5, 1971, Ser. No. 196,205 Int. Cl. B01j 11/40; Cg23/02 U.S.Cl.*252-455 R- v "z'Claims V ABSTRACT OF THE-DISCLOSURE i In ahydroconversion process wherein a hydrocarbon feedstockiscoiitact'edwith solid catalyst particles preparedly forming a hydrogel"and thenshaping the hydrogel in't'o'a pellet, and 'whe'r'eiiis'aid'contacting 'is carried out at a temperature between 400 and -9'00 F.,'a'nd a r hydrogen partial pressure between 100 and 10,000 p.s.i.g., theimprovement when comprises pfrparing said catalyst by; adding tosaidhydrogel a catalyst fines -water mixture containing at least T0"weight ercent free water and at.

" incorporated in the catalyst material'befo're the catalyst materialisshaped-into the final catalyst pellet.

The present invention afior'ds a process-for hydrofining heavyhydrocarbon charge stocks for the primary purpose of efi'ecting theelimination of nitrogenous and sulfurous compounds, and providingadditional advantages through conversion of the pentane-insolu'bleportion of such heavy hydrocarbon charge stocks into more valuablepentanesoluble hydrocarbon oils. The. catalyst pellets which are formedin the process of the present invention are .par- "ticularlyadvantageously used in hydrodesulfurization of Patented Mar. 5, 1974compounds, petroleum crude oils contain greater quantities of sulfurousand nitrogenous compounds than are found in the lighter hydrocarbonfractions including gasoline, kerosene, middle-distillate gas oils, etc.The nitrogenous and sulfurous compounds may be at least in partconverted, on being subjected to a hydrorefining process, intohydrocarbons, ammonia, and hydrogen sulfide, the

latter being readily removed from the system in a gaseous phase. Thecatalyst pellets which are used in the hydroconversion process of thepresent invention can be prepared by various prior art means (except forthe inventive features I, which will be discussed hereinbelow) includingthe aqueous gelation means as described, for instance, in J. Jaife U.S.Pats. 3,280,040 and 3,493,517, or in Kuwata et al.

' US. Pat. 3,530,066. Thus, general methods of preparing hydrogels orcoprecipitates are known in accordance with the prior art.

7 The addition of fine particles to a gel or s01, such as silica sol,has been described in patents such as US. Pat. 3,414,525 and US. Pat.3,530,066. US. Pat. 3,414,525

'jrelates toqthe addition of crystalline aluminosilicate to f a silicasol before the silica sol is aged and formed into a final catalystpellet. US. Pat. 3,530,066 is directed to making a catalyst pellet whichis 85 to 99 percent fine refractory particles with 1 to 15 weightpercent of alumina hydrogel. According to the 066 patent, the fineparticles are obtained by drying and calcining alumina and thencomminuting the alumina into particles of 20 to 100 petroleum crude oilsor heavy fractions of petroleum crude oils suchf asatmospheric,distillation column bottoms, or vacuum distillation columnbottoms, or solvent deas- "phalted heavy oils. Y

J Petroleum crude oils, "and the heavier hydrocarbonv fractions and/ordistillateswhich may be'derived therefrom, generallycontainnitrogenousand 'sulfurous com- "pounds'in relatively largequantities: In addition, petroileumcrude oil-iscontaminated by theinclusion therein of detrimental quantities of organometalliccontaminants having the tendency to exert deleterious effects upon acatalytic composite which is employed in various processes 1 to whichthe crude oil or heavy "hydrocarbon fraction "may be subjected. The mostcommonmetallic contaminants are nickel and vanadium, although othermetals including o copper e c-away be pres nt-T e e metals y Occur Wi ithe qnrlssilin ale e y o su s: y ay exist as metal oxides or sulfides,introduced as metallic scale or particles; they may be present in theform of soluble salts & of such metals; generally, however, they existin the form or organometallic compounds, such 'as' metal porphyrins I"and various" derivatives "'ther'eof. Although those' metalliccontaminants existing" in the form" 'o'ff'OXide'fand/or sulfide "scale"may *be'='removed" by a relatively simple washingfiltering procedure,and -.,the water-soluble saltsare at least in part removablebywaterwashing followed by' a subsequent dehydration, technique, a muchmore severe treatment is required to remove the organome tall iccompounds, and to the extent that the resulting 'criide'oil or heavyhydrocarbon fraction becomes suitable for further,

microns in size. These dried fine particles are added to a verysmallportion of alumina hydrogel, and this mixture is kneaded and then shapedinto a catalyst particle having pore sizes of 1,000 to 50,000 angstroms.

SUMMARY OF THE INVENTION It" is important in the process of the presentinvention to add the catalyst fines as a catalyst fines-Water mixture.Thus, the process of the present invention differs from prior artprocesses suggesting the addition of dry fines to hydrogel materialbefore the gel material is shaped into a catalyst pellet.

The present invention is based "the removal of organometalliccontaminants, and in the 1 I largely on our finding that the use of thecatalyst pellets obtained in accordance "with the present inventionshows surprisingly high activity and also surprisingly low fouling ratesin hydroconversion service, particularly in hydrodesulfurization ofheavy oils such as crude oil atmospheric-distillation column bottoms,

1 vacuum distillation column bottoms, or deasphalted heavy the catalystof the autofining operation.

- (a) forming a hydrogel of oils.

In general, the hydroconversion operating conditions for which catalystsprepared in accordance with the present invention are to be used are asfollows:

Temperature F 400 900 Pressure p.s.i.g :10020,000 Liquid hourly spacevelocity 0.1l0.0 Hydrogen feed rate (1) Typically 500 to 10,000s.c.f./bbl. of oil feed, although pr s nt, inve i n. c a so heuse inwith the present invention a processis provided for preparinghydroconversion catalysts which comprises:

alumina, silic'a, or alumina- -silica precursors; I T (b) adding to saidhydrogel a catalyst fines-water mixone containing at least 10 weightpercent free water H I A and at least weight percent total water beforethe subsequent processing,,=In addition to the or-ganometallic hydrogelis shaped into a pellet;

fines mixture; and

(d) shaping the hydrogel with the added catalyst fines into a pellet.

It is particularly preferred to shape the hydroconversion catalyst byextrusion, for example, extruding the gel mixture through a die with anopening of about 5 to A -inch in diameter.

It should be understood that in the present specification the termcatalyst pellet may be used to mean catalysts formed by a pelleting orcompression method on dried catayst powders, but preferably is used in abroad sense to cover catalyst formed by extrusion and agglomeration ofwet mixtures, and to distinguish the final catalyst from the sometimesvery tiny particles which make up the final catalyst pellet.

The term hydrogel is also used in a broad sense to include shapelessprecipitates and true all-embracing solid gels. Thus, in general, theterm hydrogel is used to include precipitates, which may be in slurry orfilter cake form, of one or more of the materials which are the catalystpellet precursors. The catalyst pellets used in the process of thepresent invention preferably comprise alumina, silica, oralumina-silica. The catalyst pellets used in the present invention alsopreferably comprise one or more hydrogenation components such as GroupVI-B and/or Group VIII metals, usually in the oxide, sulfide orelemental form. Typical hydrogenation components thus comprise :Ni, Co,Pd, M0 and W. i

The term catalyst fines is used herein to mean fine solid particles.Particularly preferred are fine particles which are obtained by grindingup or otherwise finely dividing various waste materials from variouspoints in the catalyst manufacturing procedure, said points being afterat least a catalyst precursor gel has been formed such as an aluminaprecursor. It is most preferable to employ as said catalyst fines wastematerial obtained from a point in the catalyst manufacturing procedureafter all the catalyst precursors are present in the catalyst materialas, for example, waste material from an extrusion step, or from a dryingstep, or from a calcining step. Preferably, the size of the catalystfines is less than 1,000 microns in diameter, and more preferably lessthan 50 microns in EXAMPLES Example 1 Catalyst A is a hydrogelcoprecipitate of the type disclosed and claimed in J. Jafie U.S. Pat.No. 3,493,517. Composition is:

Percent NiO 10.2 M00 30.0 A1 0 43.3 TiO 10.0 P 0 6.5

. Through adjustment of drying and calcining conditions,

a catalyst particle area of 284 m. cc. was obtained with averagemicropore diameter: 100 angstroms. I

The average micropore diameter was calculated by dividing the porevolume (cc./g.) by the surface area (mi /g.) and multiplying by 40,000..7

' Catalyst 3 was prepared similarly as catalyst A, with the exceptionthat 50 percent of the final catalyst was comprised of finely pulverizedcatalyst powder obtained from an air attrition mill (micronizer). Thedried catalyst fines were uniformly distributed by intensive mullinginto the wet hydrogen matrix. The 'mixture'was extruded, dried andcalcined by conventional means. Catalyst particle area was 237 m. /cc.with average pore diameter =angstroms.

Example 3 Catalysts A and B were compared for desulfurization of a heavyArabian atmospheric residuum of inspections:

From the tests the activity (starting temperatures) and fouling rateswere:

' Catalyst A: 726 F., 0.02 F./hr.

Catalyst B: 724 F., 0.04 F./hr.

Thus it is seen that the initial catalyst activities were similar, butthat catalyst B, containing recycled dried fines, was not as stable ascatalyst A.

Example 4 Catalyst C was another preparation of catalyst A, whichthrough adjustment of drying and calcining conditions had a particlesurface area of 353 mfi/cc. with average micropore diameter=86angstroms.

Example 5 Catalyst D was. prepared by identical processing as catalystC, with the exception that 15 percent wet ground fines was added to thehydrogel prior to further processing. The fines were prepared in a 5percent. solids-water slurry by passing dried catalyst and water througha Manton Gaulin homogenizing pump. The groundfines slurry was mixed withvirgin precipitated catalyst gel.slurry, which was subsequently filteredand worked up into finished catalyst. Particle surface area of thefinishedcatalyst was 348 m./ cc. with average micropore diameter=88angstroms.

Example 6 Catalysts C and D were compared for desulfurization of anArabian vacuum gas oil of inspections:

Gravity, API 24.7 Sulfur, wt. percent I 2.4 Nitrogen, p.p.m. 816Conditions were: 4 V v LHSV 2.4 Sulfur in product, wt. percent 0.2P.s.i.g. pressure 550 S.c.f./ b. H gas rate 2400 Catalysts C and D wereof the same catalyst pellet size and were both shaped by extrusion. I

From the tests the starting temperaturesand fouling rates were!Catalystcz. 732 11, 01058 1 F./ hr. Catalyst 1): 734 H, 0.026" F./hr,,

The improved stability of catalyst D, containing recycled wet fines, isreadily apparent from the above data. The fouling rate for the catalystwith the recycled wet fines (catalyst D) was about one-half that for thecatalyst with no fines (catalyst C).

Although various embodiments of the invention have been described, it isto be understood that they are meant to be illustrative only and notlimiting, Certain features may be changed without departing from thespirit or scope of the present invention. It is apparent that thepresent invention has broad application to hydroconversion proc essesusing catalyst pellets prepared by the additionof a fine particles-watermixture to catalyst precursor precipitate followed by shaping of thecatalyst particle. Accordingly, the invention is not to be construed aslimited to the specific embodiments or examples discussed, but only asdefined in the appended claims or substantial equivalents of the claims.

What is claimed is:

1. A process for preparing hydroconversion catalyst pellets whichcomprises (a) forming a hydrogel comprising alumina, silica, or

alumina-silica precursors;

(b) adding to said hydrogel a catalyst fines-water mixture containing atleast weight percent free water and at least 80 weight percent totalwater before the 6 hydrogel is shaped into a pellet, and wherein saidcatalyst fines are solid catalyst particles comprising alumina or silicaand a Group VI-B or Group VIII hydrogenation component; and (c) shapingthe hydrogel with the added catalyst fines into a pellet. 2. A catalystpreparation method in accordance with claim 1 wherein the catalystpellet is shaped by extrusion.

References Cited UNITED STATES PATENTS 2,908,655 10/1959 Keith 252-4653,493,517 2/1970 Jafie 252-437 3,530,066 9/ 1970 Kuwata 208-3092,964,481 12/1960 Cramer et a1. 252-455 3,554,899 1/1971 Hansford208-111 3,598,724 8/1971 Mulaskey 208-111 3,682,811 8/1972 Mulaskey208-111 DELBERT E. GANTZ, Primary Examiner S. L. BERGER, AssistantExaminer US. Cl. X.R.

